In particular, the embodiments of the present invention are related to integrally formed rigid razor cutting members.
In the field of mechanical wet shavers, it has long been provided with a shaver which has a head receiving one or more cutting members.
Recently, the trend has been to provide cutting members which have a preferably L-shaped cross-section, with a cutting edge portion and a base portion which is angled with respect thereto in cross-section transverse to the length direction of the cutting members.
An example of a commercially successful such product can be found in WO 2007/147,420. Such cutting members are so-called ‘supported blades’, in that the so-called ‘cutting part’, which has the cutting edge, is assembled to a planar portion of a different part, called ‘support part’ which preferably has the L-shaped cross-section.
WO 2011/008851 also describes such a supported blade.
Yet, the assembly of these two parts raises the following problems: It is logistically difficult to handle these two different parts; it is difficult to technically handle these very tiny parts in a manufacturing apparatus operating at speeds suitable to reach the demand; it is difficult to guarantee precision of this assembly at these operating speeds, and these assemblies may corrode at the location of the attachment, thereby reducing life expectancy of the overall product.
Therefore, efforts have been made to replace these so-called ‘supported blades’ by integral bent blades. An example of such efforts can be found for example in US 2007/234,577. However, development of such an integral bent blade is very difficult. Indeed, in supported blades, it is possible to tailor the support part to its specific function, i.e. accurately providing the L-shape, and to separately tailor the cutting part to its specific function, i.e. optimized shaving performance. However, for integral bent blades, there is a need to provide a product with both excellent formability and cutting performance, while still considering the manufacturing process and cost issues.
US 2007/234,577 proposed to use a material having a composition comprised of 0.35 to about 0.43 percent carbon, about 0.90 to about 1.35 percent molybdenum, about 0.40 to about 0.90 percent manganese, about 13 to about 14 percent chromium, no more than about 0.030 percent phosphorus, about 0.20 to about 0.55 percent silicon, and no more than 0.025 percent sulfur. However, this only defines at most 18% of the material composition. According to an example, US 2007/234,577 recommends the use of a stainless steel having a carbon content of about 0.4 percent by weight, and other constituents. However, US 2007/234,577 needs to apply a local heat treatment to increase the ductility of the portion of the blade to be bent. However, this additional step is complex to implement on an industrial scale.
Another example of such efforts can be found in US 2007/124,939. However, this document defines a very general class of steels for their razor blades, namely with a very broad range of carbon content, between 0.50%-1.25%. The properties of these materials will extend in a very broad range.
The embodiments of the present invention have objectives to mitigate the drawbacks described above.